1. Field of the Invention
The present invention relates to a pixel, an organic light emitting display device, and a method for driving an organic light emitting display device using the pixel, and more particularly to a method for driving an organic light emitting display device in a digital pattern, an organic light emitting display device being driven in the digital pattern, and a pixel included in the organic light emitting display device that is being driven in the digital pattern.
2. Discussion of Related Art
Organic light emitting display devices are a type of flat panel display device that make use of organic light emitting diodes that emit light by re-combination of electrons and holes. The organic light emitting display device has advantages of high response speed and small power consumption.
FIG. 1 is a block diagram of a conventional organic light emitting display device. The conventional organic light emitting display device includes a display region 30, a scan driver 10, a data driver 20, and a timing controller 50. The display region 30 includes a plurality of pixels 40 formed at a crossing area of scan lines S1 to Sn and data lines D1 to Dm. The scan driver 10 drives the scan lines S1 to Sn. The data driver 20 drives the data lines D1 to Dm. The timing controller 50 controls the scan driver 10 and the data driver 20.
The scan driver 10 generates a scan signal in response to a scan drive control signal SCS from the timing controller 50, and sequentially provides the generated scan signal to the scan lines S1 to Sn. The scan driver 10 also generates an emission control signal in response to the scan drive control signal SCS from the timing controller 50, and sequentially provides the generated emission control signal to the emission control lines E1 to En.
The data driver 20 receives the data drive control signal DCS from the timing controller 50. Upon the receipt of the data drive control signal DCS, the data driver 20 generates data signals, and provides the generated data signals to the data lines D1 to Dm. The data driver 20 provides the generated data signals to the data lines D1 to Dm every 1 horizontal period.
The timing controller 50 generates the data drive control signal DCS and the scan drive control signal SCS according to externally supplied synchronous signals. The data drive control signal DCS is provided to the data driver 20, and the scan drive control signal SCS is provided to the scan driver 10. The timing controller 50 also provides externally supplied data Data to the data driver 20.
The display region 30 receives power from a first power supply ELVDD and a second power supply ELVSS that are located outside the organic light emitting display device, and provides them to the pixels 40. Upon receiving power from the first power supply ELVDD and the second power supply ELVSS, the pixels 40 control the amount of a current into the second power supply ELVSS from the first power supply ELVDD. The amount of the current is controlled to correspond to the data signal. The current is passed through a light emitting element in the pixel, thus generating light corresponding to the data signal. Furthermore, emission time of the pixels 40 is controlled by the emission control signal.
In the aforementioned conventional organic light emitting display device, the data signal generated by the data driver 20 is represented by a voltage corresponding to data provided to the data driver 20. As a result, the pixel 40 is charged with the voltage corresponding to the supplied data signal to display an image. In other words, the conventional organic light emitting display device controls the voltage value of the data signal to be supplied to the pixel 40, thereby controlling a luminance of light emitted in the pixel 40. However, when the data signal is provided as a voltage, a desired image cannot be displayed in the pixel 40.
Each of the pixels 40 includes a plurality of transistors. The threshold voltage and the electron mobility of transistors included in the pixels 40 may deviate from a desired value due to variations introduced during the fabrication process. Therefore, when a data signal having a certain voltage is provided to the pixels 40, due to the deviation of the transistors included in the different pixels 40 from the ideal characteristics, an image of a desired luminance cannot be displayed.